Third-graders at Boght Hills Elementary School had a unique opportunity to learn about a real-world engineering challenge during a visit from Rensselaer Polytechnic Institute’s (RPI) Engineering Ambassadors.

Professor Mohammed Alnaggar, a member of the college’s Civil Engineering faculty, and a trio of students from the RPI Engineering Ambassadors Program shared information with the elementary school students about aging bridges and roadways to raise awareness of this serious and costly problem for state and federal governments. One slide from the presentation showed a map of the U.S. that identified areas where bridges and roadways have become structurally deficient over time, as evaluated by American Society of Civil Engineers.

Students learned about the forces that can work to deteriorate the structure of bridges, and in particular, concrete surfaces where corrosion can cause pavement to crack. Air, water and salt are among the culprits responsible for corrosion. Rock salt is a compound often used by state and local highway departments—especially in the northeast—to help prevent or clear snowy and icy roads.

Boght Hills grade 3 students perform an experiment as their teacher observes.

To illustrate the harsh effects of salt, the Engineering Ambassadors guided students through a hands-on experiment using two cups of water, a small bag of salt, a red wire with a nail attached, a blue wire, a pair of electrodes and a 9-volt battery. The experiment quickly demonstrated the corrosive properties of salt on metal. When students connected the electrodes to the battery and attached the blue wire in the cup of plain water, the unsalted water bubbled. Next, within minutes of attaching the electrodes to the red wire with the nail submersed in salt water, the water began to turn various shades of orange.

Although the Engineering Ambassadors Program’s outreach is typically geared toward middle and high school students, the presentation delivered a high level of engagement in science, technology, engineering and math (STEM) activities for elementary students.

The presentation at Boght Hills also was unique in that it is directly related to research taking place in Professor Alnaggar’s lab on the RPI campus. The college’s Civil Engineering program is researching the problem of corrosion in an effort to develop innovative solutions to help strengthen America’s bridges and roads, keeping them safe for travel.

At the conclusion of the presentation, the third-graders had an opportunity to ask the Engineering Ambassadors questions. The young students also shared some of what they had learned from the experience, including what civil engineers do; the different materials bridges can be made of, including concrete, steel and wood; exposure to water can make steel rust; and that even though salt is highly effective for melting snow, it is equally detrimental to concrete.

As the third-graders lined up to return to class, Professor Alnaggar said that he looks forward to seeing some of the students again – in 12 years when they enroll as freshman at RPI.